<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>文档标题</title>
    <script>
        const days = Number(prompt("请输入天数"));
        const current = 2;
        const dayOfWeek = (days + current) % 7;
        let result;
        switch (dayOfWeek) {
          case 1: result = "星期一"; break;
          case 2: result = "星期二"; break;
          case 3: result = "星期三"; break;
          case 4: result = "星期四"; break;
          case 5: result = "星期五"; break;
          case 6: result = "星期六"; break;
          default: result = "星期日"; break;
        }
        alert(result);
    </script>
</head>
<body>
<h1>我的第一个HTML页面</h1>
<p>我的第一个段落。</p>
</body>
</html>
